The callee/caller saved information is not constant accross different
ABI's, so don't make it constant. Instead, all BE that still use beabi
provide a callback now.
This allows to implement support for x64_64/Win32 and is a necessary step
for the combined x86 BE.

[r28145]

[r28127]

[r28073]

[r28038]

[r27828]

[r26550]

- Add a generic requirements+register+flag dumper to bearch; This avoids all
  backends/benode having their own slightly different dumpers
- Lots of cleanups in the backends along the way

[r26542]

	* benodes store the out register requirements in backend_info now
	  (this is work towards killing the register_requirement callbacks)
	* ir_graph has a pointer to beirg now
	* Other cleanups

[r26540]

[r22888]

[r22867]

[r17143]

[r16009]

[r15859]

[r14751]

[r14743]

[r14604]

[r14517]

[r14193]

[r13565]

[r13511]

[r13414]

[r13398]

- Started working on flags

[r12716]

[r12617]

- more work on state registers for x87 fpu rounding modes

- Replace limit callback in register requirements with a simple bitset
- Fix backends, generators and the rest of the code for the change register
  requirements structure
- Eliminated the custom register_requirement structures in the backend, they
  are pointless now, use the normal arch_register_req_t
- Fix TEMPLATE backend
- Extract emitter framework from ia32 and provide generic header/code for it
- Port TEMPLATE backend to new emitter
- Extract gas specific emit stuff (declarations, sections) from ia32 backend
  and provide it as generic header/code. Make TEMPLATE backend use that
- Remove several FIRM_DBG_REGISTERs from functions which are called very often.
  Before we had millions of string hashtable lookups because of that. The
  prefered way is to have 1 static debug module per file and initialize it in
  the module constructor. No passing around in environment structs and in no
  case should you dynamically register it in single functions.

added default DUMMY unit
register can be connected to units

made UNKNW, NOREG and vfp registers virtual

while limiting registers: clear ignore registers before applying limits from config, otherwise esp is always cleared

make the arch_register_t declarations extern in the header and place definitions in the source